Grand Theft Auto: San Andreas

I tried to copy san andreas on to my hard drive and there were errors so the downloading process was cancel. I tried Nero, DVD Decrypter,..everything and i still come up with errors. What am I doing wrong?

when i decrypted and burned san andreas it said there was an error with volume control or something like that. i finished it anyway and the game came out fine except for having the problems the old grand theft auto games had when they got worn out. the infamous error reading grand theft auto 3/vice city/san andreas ps2 disc message screen and annoying dissapearing reappearing buildings and background. but it is only sometimes